Mercury switch

ABSTRACT

An attitude insensitive mercury relay included in a hermetically sealed nonmagnetic enclosure composed of a header and header cap, welded together in a high-pressure hydrogen atmosphere, including one or more stationary contacts extending insulatedly into the enclosure and a magnetic diaphragm as armature, in the form of a single planartight spiral having physically separated turns. In one form of the device, the interior of the enclosure and the diaphragm may be mercury wettable, excluding only an insulating feedthrough button for a stationary contact, and also excluding a portion of the face of the contact which is intended to sustain impact by the armature, the mercury wettable portion of that face being indented with respect to the impact area, and the quantity of mercury in the enclosure being sufficient, but only sufficient, to sustain a thin layer of mercury on the mercury wettable surfaces. In other forms the enclosure may be nonmetallic, e.g., ceramic, provided with mercury wettable screen surfaces.

United States Patent Bitko Inventor:

Assignee:

Filed:

Appl. No.:

US. Cl. ..335/58, 200/152 Int. CL... ..I-l0lh 1/08 FieldofSearch ..335/49, 51, 52, 55, 56, 57,

[56] References Cited UNITED STATES PATENTS 3,144,533 8/1964 Donath ..335/58 3,529,268 9/1970 Rauterberg ..335/56 FOREIGN PATENTS OR APPLICATIONS 326,408 9/1920 Germany ..335/196 Feb. 29, 1972 Primary Examiner-Harold Broome Attorney-Hurvitz and Rose [57] ABSTRACT An attitude insensitive mercury relay included in a hermetically sealed nonmagnetic enclosure composed of a header and header cap, welded together in a high-pressure hydrogen atmosphere, including one or more stationary contacts extending insulatedly into the enclosure and a magnetic diaphragm as armature, in the form of a single planartight spiral having physically separated turns. in one fon'n of thedevice, the interior of the enclosure and the diaphragm may be mercury wettable, excluding only an insulating feedthrough button for a stationary contact, and also excluding a portion of the face of the contact which is intended to sustain impact by the armature, the mercury wettable portion of that face being indented with respect to the impact area, and the quantity of mercury in the enclosure being sufficient, but only sufficient, to sustain a thin layer of mercury on the mercury wettable surfaces. in other forms the enclosure may be nonmetallic, e.g., ceramic, provided with mercury wettable screen surfaces.

31 Claims, 9 Drawing Figures PATENTEDFEBZS I972 SHEET 2 BF 2 INVENTOR SHELDON S. B\TKU ATTORNEYS MERCURY swrrcrr BACKGROUND OF THE INVENTION The initial impetus toward the relay of the present invention the enclosure for the switch, butis inadequate to form a freeflowing pool of mercury regardless of the attitude of the switch. That patent discloses three distinct species of its basic concept, two ofwhich employ a slug, freely' riding ona layer of mercurybecause it is unwettable by the mercury, and the other being a reed switch. It has been believed crucial to the Donath device'toutilize a very small physical structure and large wettableareas relative to the size of the device, in order to solve a crucial problem, i.e., the maintenance of a liquid layer overlong-periods of time'as the relay operates. Liquid on the switch contacts is continuously being lost by impactand forother reasons, and must be able to replenish itself automatically as a layer, if the switch is to remain'operative, re-

gardless of the attitude of the switch.

Thepresent invention employsa nonmagnetic'metallic envelope, a stationary contact or contacts, anchored via a nonwettable insulator or insulators in a wall or walls of the envelope, andanarmature in the form'of a single spiral, suchas is used as amainspring in a watch. The turns of the spiralhave spacings adapted to hold mercury, and the entire helix is mercury wettable, and'all the turns of'the spiral, of which there are many, interact with each other and with themercury. The header could be magnetic and the cap nonmagnetic, or vice versa,or both' headerand cap could be magnetic if nonmagnetic windows are provided in the magnetic element to permit entrance of-magnetic'flux. It follows that the spiral provides a very considerable'high' surface tension reservoir of mercury as a'continuo'us thinlayeron itssurface, and the layer readily reintegrates itself whenbrokenby operationof the relay. The spring can-besmall'or large, and-there is no longer a requirement that the switch'be small, as in theDonath device. It can be'madetohandle 50 aof current if desired. The interior walls ofthe enclosure, which is in the form ofa header and cap welded togeth'enaremercury wettable, except for theinsulatorswhich enable stationary contacts to feed through. The spiralis physically-securedat its perimeter to the envelope, either byweldingor-clamping or it maybe loosely laid on a circumferential securing'slot, and the envelope'can then constitute a switch output electrode, the spiral operating as a damped'reed. Damping factors can be designed for reed vibration frequency. The very long reed spring can be made extremely flexible, so that in operation it can impact against the envelope but its impact against the envelope has no effect on switching and does result in'redistributing mercury. In the present device the spring permits a major reservoir of mercury, and the-structure lends itselfto fabrication in relatively large diameter, thin envelopes, which are inexpensive to make.

Diaphragm-type switches which do not employ mercury are commercially available. These employ diaphragms which have circular slots or plural spiral slots. There are, however, no

spiral slotted discs, having many turns, say four, presently employed in relays, so that the latter represent highly elongated, but compact reeds. The spring device or elongated reed of this invention can be advantageously utilized in a relay which duplicates the present relay'exce'pt in that mercury isomitted,

because the "spring is remarkably flexible, and therefore responds remarkably rapidly and without oscillation or with highly dampedvibration to small magnetic forces. Damping can be controlled in terms of spring design.

' mercury.

A mercury film is one inwhich the position andshape of. the liquid'mercury do not change with respect to the solid. A mercury layer is one in which the shape ofthe. mercury changes but the mercury remains on average in contact with the-solid, despite changes of attitude of the surface, or subjection thereof to shock or vibration. A mercury pool is one. inwhich both the shape. and location of the mercury change ona statistical and transient basis, the pool, at least as a whole; not being relatively permanently attached to a wettablesurface.

When a mercury relay operates, mercury flies .in all directions for each impact between the contacts. In addition, mercuryis displaced due to forces, i.e., those of gravity, vibration and shock, temperature gradients and forcessof surface tension. It is essential that a mechanism-be present in a mercury relay for relocating mercury which has been. displaced, to locations such that contacts will not be short circuited,'andwin the present system this must occur regardless of switch rattitude.

It can be shown by mathematical analysis that the available surface tension force to restrain a given volume of mercury on a mercury wetted surface is proportional to the length of 'the edge of the surface. It follows that breaking up a surface into small discrete areas increases the net surface tension forces spiral spring has total surface proportional to its length, and

the cap and header inner surfaces can be improved in respect to surface tension if lined with spiral elements, or withfine mesh screening or the like.

The advantages which the present system presents'overrthe structure of Donath is that a free slug is avoided, movement-of the latter requiring considerable energy expenditure,=andethe only frictional forces which need be avoidedare those of the spring and those due to viscosity of mercury, leading to high sensitivity. Second, the enclosure of the presentinvention can be resistance welded closed, and this can be .done in a.-250 p.s.i. hydrogen atmosphere, at low cost. The Donathdeviceas presently designed cannot be-welded closed, and hence cannot enclosehigh-pressure gas. Third, the present device can be made large, and therefore capable of carrying high current, which is not true of the Donath unit. The Donath unit is. a high-precision unit, in terms of fabrication techniques and thereforetends to be expensive. The present unit is extremely inexpensive because it lends itself to mass production.

SUMMARY OF TI-IE'INVENTION An attitude insensitive relay within a hermeticallysealedenclosure, having a single internal spiral spring as itsmovable contact, and in a preferred embodiment, wherein the'major portion of the interior of the enclosure is mercury wettable and covered by a thin layer of mercury, the total quantity'of mercury being insufficient to form a freely flowable permanent poolin the relay in addition to the thin layer, for-any possible attitude of the relay.

BRIEF DESCRIPTION OF THE DRAWINGS The above and still further objects, features. and advantages of the present invention will become apparent upon consideration of the following detaileddescription of one specific embodiment thereof, especially when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a view in section'of a switch according to themvention, which is monostablein open condition and whichcan be closedby applying a magnetic field, as'by means-ofaperman'ent magnet;

FIG. 2 is a view in section'of a modification ofthedevicerof FIG. 1, having two stationary contacts;

FIG. 3'is a view in section of an electromagneticmercury relay according to the invention; biased open'and closedwin responseto coil energization;

FIG. 4 is a view-in section of a bistable single contact electromagneticmercuryrelay according to the invention;

FIG. 5 is a view in'section of a bistable mercury relay;

FIG. 6 is a view in plan of a spiral armature according to the invention;

FIG. 7 is a view in section of the armature of FIG. 6, ener tion, having a mercury wettable internal enclosure walls covered with nonwettable screen, to increase the net linear length of wettable surface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, 10 is a header cap fabricated of nonmagnetic material which is internally mercury wettable. Welded to the cap 10 is a nonmagnetic header 11 which is internally mercury wettable. The header 11 and its cap 10 are welded together by a circumferential resistance weld 12. Through the header 11 insulatedly extends a contact pin 14, in the form of a cupronickel cored rod; other metals may be employed for the core, so long as they provide a mercury wettable recess, the outer layer of core is a nonwettable covering 15 which extends, farther than does the core, interiorly of the envelope E formed by header l1 and cap 10. The pin 14 is magnetic and is insulated from header 11 by a glass seal 16 which is nonwettable. A spiral armature 17 is welded to the inside of the header cap 10, at its outer terminal 18. The spiral armature 17 is a multitum spiral and in fact the spiral acts as a long reed having its movable terminus 20 at the center of the spiral. The length of the spiral may be about 3 inches, whereas the diameter of the spiral is about inches.

The spiral 17 is treated to be mercury wettable, and the space between the spiral l7 and the inner surface of header cap is filled or largely filled with mercury, this space being fillable by a layer of mercury. The space between the turns of the spiral are also filled with mercury (as is the interior surface of the spiral) because of the closeness of the spacing (0.0075 inches).

The only surfaces within the envelope E which are not mercury wettable are (1) the surface of insulator 16, and the outer surface of contact pin 14. The core of the contact pin is mercury wettable but its inner end is set back slightly from the inner end of the pin 14, so that the core never physically contacts the spiral armature, but the core does carry mercury and hence can make proper electrical contact with the armature.

The spiral armature 17 can now be brought into contact with the inner end of contact pin 14 by means of a magnetic field produced by a permanent magnet M, when the latter approaches the switch. The spiral armature can be maintained in open position by its own resilience, but preferably this is done by a circular radially magnetized bias magnet 21 mounted on a rod 22 axially secured to header cap 10. Use of a symmetrical magnetic field provides a uniform bias on all turns of the spiral l7, tending to pull the spring away from the contact. The spring, for some designs, would move until stopped by the inner wall of the cap 10. If this results in sticking, or implies too great a movement, a nonwettable projection can be supplied to provide a stop (not shown).

In FIG. 2 is illustrated a double ended relay, i.e., one having two stationary contact pins 30, 31 and a single spiral armature 32. The enclosure E includes a nonmagnetic header 33 and a nonmagnetic cap 34, which are welded to form a cylindrical enclosure E at joint 25. The total diameter of the header in one design is 0.325 inches. All other dimensions are to scale in the drawing. The contact pin is made of copper alloy cored sealing alloy, nonmagnetic, while contact pin 31 is copper alloy cored sealing alloy, magnetic. The contacts are mercury wettable only at their cores as 36, 37, which are slightly recessed at 38,39, and extend into the enclosure E via glass beads 40, 41. The end of armature spring 32 normally contacts contact 30, because so biased by permanent magnet 21,

though not so shown to simplify the drawings, while application of an extraneous magnetic field can serve to draw the armature to the end of pin 31, as in FIG. 1. The mercury 42 covers all areas except the insulating beads and the outer walls of the pins 30, 31. The relay of FIG. 2 is thus monostable, by reason of the location of armature 32 with respect to contact pin 30, and/or the presence of bias magnet 21.

FIG. 3 illustrates the structure of a form A relay, i.e., one which is normally open, and can be closed by energizing a coil 48 mounted on pin 31. FIG. 4 illustrates how the switch of FIG. 3 can be converted to a relay which latches closed, because of bias magnet 45, but is normally open, by the addition of energizing coils 46, 48. FIG. 3 is essentially the same as FIG. 1 in principle, but is drawn to scale, the diameter of the enclosure being 0.325 inches. Accordingly, the small numerals of reference are employed in FIGS. 1 and 3. FIG. 3 shows the location and quantity of the required mercury layers a bit differently than in FIG. 1, but this occurs as gaps from armature to wall are varied. Adding a latching magnet 45 of radial magnetization, and a further coil 46 mounted on magnetic pin 47 welded to header 48, produces the result that if form A coil 48 is energized, armature l7 pulls over to contact pin 14, where it is latched by permanent magnet 45. Energization of coil 46 overcomes the latch and opens the switch, which then remains open. Magnetic pin 47 does not extend into the enclosure, since it is not needed as a contact.

A form C relay is illustrated in FIG. 5, which is distinguished from FIG. 2 in that both contact pins must be magnetic, whereas this is optional as to pin 36 in FIG. 2; and the armature 17 is centered, so that the switch is normally open at both contacts. Two coils 46, 48 are employed, and two permanent magnets 45, 45a, identically radially magnetized to make a latching bistable switch. I-Iere magnets 45, 45a must be strong enough to latch when the armature is deliberately activated.

If the 45 magnet is omitted latching will occur only on side A. By employing a strong enough magnet 45 and only coil 46, a monostable switch results, while if no permanent magnets are employed, and both coils, type center-off operation with no latching is achieved.

FIG. 6 illustrates an effective single turn spiral, formed by etching or stamping a spiral slot 50 in a thin disc of magnetic metal, plated or treated to be mercury wettable, and employs I a 0.0075 inch etch through width and a 0.020 inch land 51. The spiral is generated in terms of concentric circles joined by straight lines, and therefore is not a true geometrical spiral. This is for manufacturing convenience. By the same token plural spirals could be employed, but there is considerable advantage in employing one spiral in that this provides the most flexible and most sensitive construction, in that it corresponds with a reed of maximum length. The reason is that a single reed can be extremely long, whereas for multiple spirals, i.e., multiple reeds each reed is short, relatively, and therefore stiff, relatively. The total number of turns utilized in the spiral depends on the sensitivity desired, and can be controlled, as can spiral thickness, spiral width, material temper, and the like.

The appearance of the spiral armature in process of being pulled can best be indicated as in FIG. 7, which is exaggerated. The spiral is distorted since its outer edge is held against motion, while its center moves into contact with the end of pin 14. The latter has a recessed, mercury wettable core 15, but a nonwettable outer layer 15a. Due to the recessing it is the nonwettable end 15b of the pin 14 which is impacted by the armature. The recessing is sufficiently shallow that a drop of mercury can contact the center 52 of armature 17. When fully actuated the center 52 will contact the end 15b of pin 14.

It has been noted supra that ability to retain mercury is a function of the total length of retaining element, and not area, in the sense that total surface tension force is increased as a function of length. This length can be increased, as by securing to the interior surfaces of the header and cap, spirals, screens, or other devices which break up the surface and thus present a greater length of edge.

This has been done in the embodiment of HG. 9, wherein nonwettable spirals, or screens, are welded to the side walls of header and cap 10,11. This breaks up the wall surface into many small areas, but in the process increases the total length of surface to which mercury can attach, and thereby intum the available force.

In- FIG. 8, the enclosure header and cap, 80, 81 are fabricated of ceramic, the inner walls of the enclosure being provided with a wettable layer of screen, 82. In other respects the relays of FIGS. 8 and 9 may utilize the operating and structural features of therelays of FIGS. l-5, or stated otherwise, the enclosures of FIGS. 8 or 9 may be utilized in the systems of FIGS. 1-5 inclusive at will.

There is some danger that relays or switches of. the type described will latch whenlatching is not desired due to surface tension forces, or the latter plus magnetic forces where permanent magnets are employed. This can occur in response to shock, attitude, vibration, acceleration, and the like. To avoid this contingency permanent magnets aligned with-the planeof the spiral armature canbe provided. The armature. then tends to align itself with the field provided by the permanent magnets.

in FIGS. 8 and 9, permanent magnets 85, are employed to maintain-the-armatures l7 biased planar. This is an expedient usable in any of the relays of FIGS. 1-5. It is adequate. to employ rodmagnets for the purposebut circular magnets encompassing the enclosures are more effective.

Because the switch is extremely sensitive, it can be controlled'by a permanent magnet rather than by a coil. If the permanent magnet is mounted on a moving member, the combination then can be considered a limit switch requiring no physical contact (see FIG. 1

In this respect it is found that a permanent magnet can be used to move the armature in'either direction, depending on the location of the magnet relative to the armature. if the magnetafieldis symmetrical with respect to the center line or axis of the armature, the presence of the magnet always attracts the armature towards the magnet. But if the field is asymmetrical or off axis repulsion can occur, or attraction. The reason is that the armature, when viewed along a radius and when magnetized presentsa linear array of North and Southpoles. If the array. is approached by a North pole, off its axis, that North pole may be proximate a South pole and cause attraction or proximate a North pole and cause repulsion. This is clear enough when the armature is magnetized by some device other than the approaching North pole, but it is empirically determinable that the same effect occurs in respect to a magnetically unpolarized armature, i.e., the fields induced by an approaching single pole may be such as to effect attraction or repulsion, according to the location-of the pole relative to the armature.

Generally, the armature may be welded into the enclosures. However, it is feasible to provide a few protuberances on either the cap orthe header, or both, which serve to clamp the armature in place between the cap and the header.

While I have described and illustrated one specific embodiment of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

What is claimed is:

l. A mercury switch, comprising a concave dish of nonmagnetic material impervious to mercury,

a diaphragm enclosing the open side of said concave dish,

said diaphragm being a spiral spring having an axis,

said diaphragm having a mercury wettable surface,

an elongated stationary contact having its end spaced from said helical spring-and located parallel to said axis,

said stationary contacthaving its contact end facing said helical spring and being mercury wettable and being fabricated primarily of magnetic material,

a button of insulating material extending through said concave dish, said stationary contact extending through said button, and

aclosure of nonmagnetic material'for said concave dish.

2. A relay comprising an envelope,

a quantity of mercury located within said envelope,

contacts comprising a spiral spring armature and a stationa ry pin contact opposed to said spiral spring'armature, said contacts including opposed mercury wettable surfaces,

at least one mercury unwettable surface within said ene velope insulatedly isolating said contacts from each other,

the total quantity of mercury within. said. envelope being only sufficient to form athin layer of mercury on saidmercury wettable surfaces and. insufficient to form apoolof mercury in addition to said thin layerrof mercury for any attitude of said relay.

3. A mercury relay, comprising a hermetically sealed envelope,

a flat circular plate of ferromagneticresilient material: having approximately circular interconnected slots therethrough and forming the armature of the relay,

first and second ferromagnetic pins extending insulatedly through said envelope in opposite directions toward said flat plate,

said envelope including mercury nonwettable insulators: through which said pins extend, the interior surfaceof said envelope exclusive of said insulators and the surfaces of said flat plate and'at least the inner ends of said pins being mercury wettable, and there being only sufficient mercury within said envelope toform layers of mercury covering said mercury wettable surfaces, but insufficient mercury to form a poolin addition to the mercury of said. layers, which pool might cover the inner surfaces of one of said insulators.

4. Thecombination according to claim 3, wherein said insulators are glass, said pins include copper alloy cores which are mercurywettable and have a covering of magnetic material, said cores being undercut with respect to said covering whereby only said covering is impacted by said armature.

5. The combination according to claim 4', whereinsaidenclosure is nonmagnetic.

6. The combination according to claim 5, wherein said envelope is made of two concave metallic headers welded to leave a cavity within which said armature subsists, said arma' ture being secured only adjacent its edge to at least oneof said headers.

7. A magnetic relay, comprising ahermetically sealed metallic enclosure including a header and a header cap,

a thin resilient flat armature plate'of ferromagnetic'material.

located internally of said enclosure and having'at least one generally spiral complete turn slot,

means securing the outer edge of said armature plate immovably to said enclosure,

a fixed elongated pin contact,

means insulatedly sealing said'pin contactthrougha wallof said enclosure, said pin' contact having an endin-proximi' ty to said plate, said plate and said pin being ferromagnetic,

a coil surrounding said pin,

the surface of said plate and the surface of the end of said. pin and adjoining portions of the interior surfaceof said' sealed enclosure being mercury wettable, and said means insulatedly sealing being mercury unwettable, and a; volume of mercury within said sealed enclosure sufficient only to supply a layer of mercury on all said wettablesurfacesand insufficient to form a pool of mercury in addition to said layer, whereby saidrelay is position insensitive.

8. An attitude insensitive mercury relay, comprising a cylindrical enclosure having end plates and having amercury wettableinterior surface,

a mercury wettable thin flexible armature located interiorly of said enclosure and extending transversely of the axis of said cylinder,

at least one mercury wettable stationary contact of magnetic material insulatedly extending through a wall of said enclosure perpendicularly of said end plates into proximity with said flexible armature in its unflexed condition,

said mercury wettable interior surfaces including a portion which is unwettable by mercury and which surrounds said stationary contact, and

a quantity of mercury in said enclosure which is only adequate to form a thin layer of mercury on said wettable surfaces.

9. The combination according to claim 8, wherein said armature is a reed.

10. The combination according to claim 8, wherein said en closure is a ceramic enclosure.

11. The combination according to claim 8, wherein said enclosure is metallic, and wherein a lead through glass insulator is provided in one of said end walls for said stationary contact.

12. The combination according to claim 8, wherein said-armature is a spiral multiturn reed.

13. An attitude insensitive mercury relay, comprising a hermetically sealed ceramic enclosure having generally parallel end plates and internal mercury wettable surfaces,

a mercury wettable thin flexible diaphragmatic armature extending parallel to said end walls and coextensive therewith,

at least one stationary mercury wettable contact extending through one of said end walls into contact with said flexible armature when said flexible armature is flexed toward said stationary contact,

magnetic means for moving said flexible diaphragmatic armature toward and away from said stationary contact, and

a quantity of mercury in said enclosure only adequate to form opposed thin mercury layers on said flexible armature and said wettable surfaces and said stationary contact.

14. A relay comprising an envelope,

a quantity of conducting liquid having high surface tension located within said envelope,

conducting surfaces and insulating surfaces separating said conducting surfaces within said envelope,

at least one of said conducting surfaces forming at least part of said envelope,

said conducting surfaces including relatively movable areas substantially wettable by said liquid, and including one movable contact constituted of a thin resilient magnetic diaphragm secured at its rim to said envelope, the quantity of said liquid within said envelope being substantially adequate to cover said substantially wettable areas with a thin layer of said liquid and inadequate to fonn a permanent and substantial pool of said liquid in addition to said layer regardless of the attitude of said relay.

15. A switch, comprising an envelope,

a contact within said envelope including a resilient diaphragm anchored at its rim,

a further contact within said envelope and forming part of said envelope,

said contacts including mercury wettable surfaces,

at least one mercury unwettable surface within said envelope insulatedly separating said contacts,

a total quantity of mercury within said envelope being only adequate to form a thin layer of mercury on said mercury wettable surfaces held to said mercury wettable surfaces by surface tensions, said surfaces interchanging mercury during operation of said switch.

16. The combination according to claim 15, wherein said resilient diaphragm is a single spiral spring having more than one turn.

17. A switch, comprising a concave dish of resistance weldable metal, a magnetic armature located in said dish and electrically connected to said dish, a stationary contact, an insulator extending insulatedly through said dish from exteriorly to interiorly of said dish, said stationary contact extending through said insulator, a closure of resistance weldable metal peripherally welded about the periphery of said dish to form a hermetically sealed enclosure, wherein said magnetic armature and interior surfaces of said enclosure include mercury wettable areas and wherein said insulator is mercury unwettable, and wherein a quantity of mercury within said enclosure is only sufficient to sustain a thin layer of mercury on the mercury wettable surfaces therein but insufficient to form a pool of mercury, whereby said switch is position insensitive.

18. The combination according to claim 17, wherein said enclosure is filled with gas at a pressure of the order of 250 p.s.i. 1

19. The combination according to claim 17, wherein said armature is diaphramatic.

20. The combination according to claim 17, wherein said armature is secured peripherally to the interior of said enclosure.

21. The combination according to claim 17, wherein said armature is a reed secured at least one end to said enclosure.

22. A mercury switch, comprising a concave dish of metal impervious to mercury,

a diaphragm enclosing the open side of said concave dish,

said diaphragm having a mercury wettable surface,

an elongated stationary contact extending through said dish and having its end spaced from said spiral spring in the open condition of said switch and located parallel to said axis,

said stationary contact having its contact end facing said spiral spring and being mercury wettable,

a button of insulating material extending through said concave dish, said stationary contact extending through said button, and

a metallic closure of said concave dish to form a hermetically sealed enclosure. Y

23. The combination according to claim 2, wherein said envelope is comprised of a header of resistance weldable metal and a cap of resistance weldable metal, said header and cap being resistance welded together about their peripheries to form said envelope as a hermetically sealed envelope.

24. The combination according to claim 23, wherein said envelope is filled with nonoxygen containing gas at a pressure of the order of 250 p.s.i.

25. A mercury relay, comprising a hermetically sealed envelope,

a ferromagnetic annature for said relay located interiorly of said envelope,

first and second ferromagnetic pins extending insulatedly through said envelope in opposite directions toward said armature,

said envelope including mercury nonwettable insulators through which said pins extend, the interior surface of said envelope exclusive of said insulators and the surfaces of said flat plate and at least the inner ends of said pins being mercury wettable, and there being only sufiicient mercury within said envelope to form layers of mercury covering said mercury wettable surfaces, but insuflicient mercury to form a pool in addition to the mercury of said layers, which pool might cover the inner surfaces of one of said insulators.

26. The combination according to claim 25, wherein said insulators are glass, said pins include copper alloy cores which are mercury wettable and have a covering of magnetic materi al, said cores being undercut with respect to said covering whereby only said covering is impacted by said armature.

27. The combination according to claim 26, wherein said enclosure is nonmagnetic.

28. The combination according to claim 27, wherein said envelope is made of two concave metallic headers welded together to leave a cavity within which said armature subsists,

29. A relay comprising an envelope,

a quantity of conducting liquid having high surface tension located within said envelope,

conducting surfaces and insulating surfaces separating said conducting surfaces within said envelope, i

at least one of said conducting surfaces forming at least part of said envelope,

said conducting surfaces including relatively movable areas substantially wettable by said liquid, and including one movable contact constituted of a thin resilient magnetic armature secured at at least one point thereof to said envelope, the quantity of said liquid within said envelope being substantially adequate to cover said substantially wettable areas with a thin layer of said liquid and inadequate to form a permanent and substantial pool of said liquid in addition tcTsai d layer regardless of the attitude of said relay. 30. A switch, comprising a metallic envelope, an armature within said envelope, a stationary contact extending through said envelope,

said contact and armature including opposed mercury wettable surfaces,

at least one mercury unwettable surface within said envelope insulatedly separating said contact and envelope,

a total quantity of mercury within said envelope being only adequate to form a thin layer of mercury on said mercury wettable surfaces held to said mercury wettable surfaces by surface tensions, said surfaces interchanging mercury during operation of said switch.

31. The combination according to claim 30, wherein said armature is a single spiral spring having more than one turn. 

1. A mercury switch, comprising a concave dish of nonmagnetic material impervious to mercury, a diaphragm enclosing the open side of said concave dish, said diaphragm being a spiral spring having an axis, said diaphragm having a mercury wettable surface, an elongated stationary contact having its end spaced from said helical spring and located parallel to said axis, said stationary contact having its contact end facing said helical spring and being mercury wettable and being fabricated primarily of magnetic material, a button of insulating material extending through said concave dish, said stationary contact extending through said button, and a closure of nonmagnetic material for said concave dish.
 2. A relay comprising an envelope, a quantity of mercury located within said envelope, contacts comprising a spiral spring armature and a stationary pin contact opposed to said spiral spring armature, said contacts including opposed mercury wettable surfaces, at least one mercury unwettable surface within said envelope insulatedly isolating said contacts from each other, the total quantity of mercury within said envelope being only sufficient to form a thin layer of mercury on said mercury wettable surfaces and insufficient to form a pool of mercury in addition to said thin layer of mercury for any attitude of said relay.
 3. A mercury relay, comprising a hermetically sealed envelope, a flat circular plate of ferromagnetic resilient material having approximately circular interconnected slots therethrough and forming the armature of the relay, first and second ferromagnetic pins extending insulatedly through said envelope in opposite directions toward said flat plate, said envelope including mercury nonwettable insulators through which said pins extend, the interior surface of said envelope exclusive of said insulators and the surfaces of said flat plate and at least the inner ends of said pins being mercury wettable, and there being only sufficient mercury within said envelope to form layers of mercury covering said mercury wettable surfaces, but insufficient mercury to form a pool in addition to the mercury of said layers, which pool might cover the inner surfaces of one of sAid insulators.
 4. The combination according to claim 3, wherein said insulators are glass, said pins include copper alloy cores which are mercury wettable and have a covering of magnetic material, said cores being undercut with respect to said covering whereby only said covering is impacted by said armature.
 5. The combination according to claim 4, wherein said enclosure is nonmagnetic.
 6. The combination according to claim 5, wherein said envelope is made of two concave metallic headers welded to leave a cavity within which said armature subsists, said armature being secured only adjacent its edge to at least one of said headers.
 7. A magnetic relay, comprising a hermetically sealed metallic enclosure including a header and a header cap, a thin resilient flat armature plate of ferromagnetic material located internally of said enclosure and having at least one generally spiral complete turn slot, means securing the outer edge of said armature plate immovably to said enclosure, a fixed elongated pin contact, means insulatedly sealing said pin contact through a wall of said enclosure, said pin contact having an end in proximity to said plate, said plate and said pin being ferromagnetic, a coil surrounding said pin, the surface of said plate and the surface of the end of said pin and adjoining portions of the interior surface of said sealed enclosure being mercury wettable, and said means insulatedly sealing being mercury unwettable, and a volume of mercury within said sealed enclosure sufficient only to supply a layer of mercury on all said wettable surfaces and insufficient to form a pool of mercury in addition to said layer, whereby said relay is position insensitive.
 8. An attitude insensitive mercury relay, comprising a cylindrical enclosure having end plates and having a mercury wettable interior surface, a mercury wettable thin flexible armature located interiorly of said enclosure and extending transversely of the axis of said cylinder, at least one mercury wettable stationary contact of magnetic material insulatedly extending through a wall of said enclosure perpendicularly of said end plates into proximity with said flexible armature in its unflexed condition, said mercury wettable interior surfaces including a portion which is unwettable by mercury and which surrounds said stationary contact, and a quantity of mercury in said enclosure which is only adequate to form a thin layer of mercury on said wettable surfaces.
 9. The combination according to claim 8, wherein said armature is a reed.
 10. The combination according to claim 8, wherein said enclosure is a ceramic enclosure.
 11. The combination according to claim 8, wherein said enclosure is metallic, and wherein a lead through glass insulator is provided in one of said end walls for said stationary contact.
 12. The combination according to claim 8, wherein said armature is a spiral multiturn reed.
 13. An attitude insensitive mercury relay, comprising a hermetically sealed ceramic enclosure having generally parallel end plates and internal mercury wettable surfaces, a mercury wettable thin flexible diaphragmatic armature extending parallel to said end walls and coextensive therewith, at least one stationary mercury wettable contact extending through one of said end walls into contact with said flexible armature when said flexible armature is flexed toward said stationary contact, magnetic means for moving said flexible diaphragmatic armature toward and away from said stationary contact, and a quantity of mercury in said enclosure only adequate to form opposed thin mercury layers on said flexible armature and said wettable surfaces and said stationary contact.
 14. A relay comprising an envelope, a quantity of conducting liquid having high surface tension located within said envelope, conducting surfaces and insulating surfaces separating said conducting surfaces wiThin said envelope, at least one of said conducting surfaces forming at least part of said envelope, said conducting surfaces including relatively movable areas substantially wettable by said liquid, and including one movable contact constituted of a thin resilient magnetic diaphragm secured at its rim to said envelope, the quantity of said liquid within said envelope being substantially adequate to cover said substantially wettable areas with a thin layer of said liquid and inadequate to form a permanent and substantial pool of said liquid in addition to said layer regardless of the attitude of said relay.
 15. A switch, comprising an envelope, a contact within said envelope including a resilient diaphragm anchored at its rim, a further contact within said envelope and forming part of said envelope, said contacts including mercury wettable surfaces, at least one mercury unwettable surface within said envelope insulatedly separating said contacts, a total quantity of mercury within said envelope being only adequate to form a thin layer of mercury on said mercury wettable surfaces held to said mercury wettable surfaces by surface tensions, said surfaces interchanging mercury during operation of said switch.
 16. The combination according to claim 15, wherein said resilient diaphragm is a single spiral spring having more than one turn.
 17. A switch, comprising a concave dish of resistance weldable metal, a magnetic armature located in said dish and electrically connected to said dish, a stationary contact, an insulator extending insulatedly through said dish from exteriorly to interiorly of said dish, said stationary contact extending through said insulator, a closure of resistance weldable metal peripherally welded about the periphery of said dish to form a hermetically sealed enclosure, wherein said magnetic armature and interior surfaces of said enclosure include mercury wettable areas and wherein said insulator is mercury unwettable, and wherein a quantity of mercury within said enclosure is only sufficient to sustain a thin layer of mercury on the mercury wettable surfaces therein but insufficient to form a pool of mercury, whereby said switch is position insensitive.
 18. The combination according to claim 17, wherein said enclosure is filled with gas at a pressure of the order of 250 p.s.i.
 19. The combination according to claim 17, wherein said armature is diaphramatic.
 20. The combination according to claim 17, wherein said armature is secured peripherally to the interior of said enclosure.
 21. The combination according to claim 17, wherein said armature is a reed secured at least one end to said enclosure.
 22. A mercury switch, comprising a concave dish of metal impervious to mercury, a diaphragm enclosing the open side of said concave dish, said diaphragm having a mercury wettable surface, an elongated stationary contact extending through said dish and having its end spaced from said spiral spring in the open condition of said switch and located parallel to said axis, said stationary contact having its contact end facing said spiral spring and being mercury wettable, a button of insulating material extending through said concave dish, said stationary contact extending through said button, and a metallic closure of said concave dish to form a hermetically sealed enclosure.
 23. The combination according to claim 2, wherein said envelope is comprised of a header of resistance weldable metal and a cap of resistance weldable metal, said header and cap being resistance welded together about their peripheries to form said envelope as a hermetically sealed envelope.
 24. The combination according to claim 23, wherein said envelope is filled with nonoxygen containing gas at a pressure of the order of 250 p.s.i.
 25. A mercury relay, comprising a hermetically sealed envelope, a ferromagnetic armature for said relay located interiorlY of said envelope, first and second ferromagnetic pins extending insulatedly through said envelope in opposite directions toward said armature, said envelope including mercury nonwettable insulators through which said pins extend, the interior surface of said envelope exclusive of said insulators and the surfaces of said flat plate and at least the inner ends of said pins being mercury wettable, and there being only sufficient mercury within said envelope to form layers of mercury covering said mercury wettable surfaces, but insufficient mercury to form a pool in addition to the mercury of said layers, which pool might cover the inner surfaces of one of said insulators.
 26. The combination according to claim 25, wherein said insulators are glass, said pins include copper alloy cores which are mercury wettable and have a covering of magnetic material, said cores being undercut with respect to said covering whereby only said covering is impacted by said armature.
 27. The combination according to claim 26, wherein said enclosure is nonmagnetic.
 28. The combination according to claim 27, wherein said envelope is made of two concave metallic headers welded together to leave a cavity within which said armature subsists, said armature being secured only adjacent its edge to at least one of said headers.
 29. A relay comprising an envelope, a quantity of conducting liquid having high surface tension located within said envelope, conducting surfaces and insulating surfaces separating said conducting surfaces within said envelope, at least one of said conducting surfaces forming at least part of said envelope, said conducting surfaces including relatively movable areas substantially wettable by said liquid, and including one movable contact constituted of a thin resilient magnetic armature secured at at least one point thereof to said envelope, the quantity of said liquid within said envelope being substantially adequate to cover said substantially wettable areas with a thin layer of said liquid and inadequate to form a permanent and substantial pool of said liquid in addition to said layer regardless of the attitude of said relay.
 30. A switch, comprising a metallic envelope, an armature within said envelope, a stationary contact extending through said envelope, said contact and armature including opposed mercury wettable surfaces, at least one mercury unwettable surface within said envelope insulatedly separating said contact and envelope, a total quantity of mercury within said envelope being only adequate to form a thin layer of mercury on said mercury wettable surfaces held to said mercury wettable surfaces by surface tensions, said surfaces interchanging mercury during operation of said switch.
 31. The combination according to claim 30, wherein said armature is a single spiral spring having more than one turn. 